Methods of preparing para-xylene from biomass

ABSTRACT

Methods or preparing para-xylene from biomass by carrying out a Diels-Alder cycloaddition at controlled temperatures and activity ratios. Methods of preparing bio-terephthalic acid and bio-poly(ethylene terephthalate (bio-PET) are also disclosed, as well as products formed from bio-PET.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/636,326 filed Apr. 20, 2012, which is incorporated herein byreference in its entirety.

FIELD OF THE INVENTION

The invention generally relates to methods of preparing bio-para-xylene(p-xylene) from at least one biomass source, as well as methods forfurther processing bio-para-xylene produced according to the presentinvention to provide bio-terephthalic acid and bio-poly(ethyleneterephthalate) (PET). The biomass source may be any of a wide variety ofstarch-, sugar- or cellulose-containing biomass sources from whichglucose can be derived.

BACKGROUND

Para-xylene (p-xylene) is an important intermediate in the production ofterephthalic acid, a monomer used in the formation of polymers such aspoly(ethylene terephthalate) (PET). Yet, traditional methods for theproduction of p-xylene suffer certain limitations. More specifically,p-xylene is commonly derived from petrochemical source materials havinga negative environmental profile and subject to significant pricefluctuations. Moreover, p-xylene is commonly prepared from processedpetrochemical mixtures containing C₈ aromatics, a complex andinefficient process given that p-xylene typically represents only fromabout 20% to about 25% of the mixture.

Bio-based plastics, or bioplastics, represent a new class of plasticsmade from biomass source materials, including food (e.g., corn) ornon-food materials (e.g., starch-producing plants). Bioplastics offerenvironmental advantages compared to petroleum-based plastics, includingthe use of renewable materials and a more limited impact of greenhousegas emissions. Bioplastics can also normally be produced using theexisting manufacturing technology, more often than not using the samereactors and machinery.

PET is among the most commonly used plastics in packaging, particularlyin the food and beverage industry. There has been increasing interest indeveloping PET packaging from biomass. Containers comprising PET derivedfrom bio-based materials, or bio-PET, are disclosed in PCT PublicationNo. 2009/120457. Commercially available bio-PET packaging containsbio-derived ethylene glycol and petroleum-derived terephthalic acid.

There remains a need for the production of terephthalic acid andp-xylene from renewable biomass sources. There is a further need toprovide bio-PET efficiently and cost-effectively using both bio-derivedterephthalic acid and bio-derived ethylene glycol.

SUMMARY OF THE INVENTION

Disclosed herein are methods of preparing bio-para-xylene (p-xylene)from at least one biomass source. Methods for further processingbio-para-xylene produced according to the present invention to providebio-terephthalic acid and bio-poly(ethylene terephthalate) (PET) arealso included. The biomass source may be any of a wide variety ofstarch-, sugar- or cellulose-containing biomass sources from whichglucose can be derived.

In one embodiment, synthesis of bio-p-xylene from at least one biomasssource comprises (i) deriving glucose from at least one biomass source(referred to herein as bio-glucose); (ii) converting bio-glucose tobiomass-derived ethanol (referred to herein as bio-ethanol); (iii)converting a first portion of bio-ethanol to biomass-derived 2-butene(referred to herein as bio-2-butene), and separately, (iv) converting asecond portion of bio-ethanol to biomass-derived 1,3-butadiene (referredto herein as bio-1,3-butadiene); (v) reacting bio-2-butene withbio-1,3-butadiene under Diels-Alder cycloaddition conditions to formbiomass-derived 4,5-dimethylcyclohex-1-ene (referred to herein asbio-4,5-dimethylcyclohex-1-ene); (vi) dehydrocyclizingbio-4,5-diemethylcyclohex-1-ene to form biomass-derived ortho-xylene(referred to herein as bio-o-xylene); and (vii) isomerizing bio-o-xyleneto form bio-p-xylene.

In another embodiment, synthesis of bio-p-xylene from at least onebiomass source comprises (i) deriving bio-glucose from at least onebiomass source; (ii) converting bio-glucose to bio-ethanol; (iii)dehydrating a first portion of bio-ethanol to biomass-derived ethylene(referred to herein as bio-ethylene); (iv) converting a second portionof bio-ethanol to biomass-derived hexa-2,4-diene (referred to herein asbio-hexa-2,4-diene); (v) reacting bio-hexa-2,4-diene and bio-ethyleneunder Diels-Alder cycloaddition conditions to form biomass-derived3,6-dimethylcyclohex-1-ene (referred to herein asbio-3,6-dimethylcyclohex-1-ene); and (vi) dehydrocyclizingbio-3,6-dimethylcyclohex-1-ene to form bio-p-xylene.

The rates of the Diels-Alder cycloadditions are optimized by controllingthe temperature of the reaction and activity ratio of the reactants.Specifically, reaction rate is increased through the use of hightemperatures and a high activity ratio of diene to dienophile.

The bio-p-xylene prepared by the methods described herein can be furtheroxidized to provide bio-terephthalic acid. The bio-terephthalic acid canbe condensed with biomass-derived ethylene glycol (referred to herein asbio-ethylene glycol) to provide a bio-PET polymer in which both theterephthalic acid component and the ethylene glycol component of thepolymer are formed from biomass source material. The bio-PET polymer canbe made into a bio-PET resin, which can then be formed into a food orbeverage container or product.

The disclosure may be understood more readily by reference to thefollowing detailed description of the various features of the disclosureand the examples included therein.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows the reaction coordinate of the Diels-Alder cycloaddition ofhexa-2,4-diene and ethylene to give 3,6-dimethylcyclohex-1-ene.

FIG. 2 shows the reaction coordinate of the Diels-Alder cycloaddition ofbuta-1,3-diene and 2-butene to produce 4,5-dimethylcyclohex-1-ene.

DETAILED DESCRIPTION

The bio-glucose starting material for the methods of the presentinvention is obtained, or derived, from at least one biomass source. Insome embodiments, two or more biomass sources are used to derivebio-glucose. A biomass source is any natural plant material orplant-derived material that contains starches (i.e. polysaccharides),including starch-containing plant material, sugar-containing plantmaterial and cellulose-containing plant material. Starch-containingplant materials include, but are not limited to, corn, maize, sorghum,barley, wheat, rye, rice, millet, barley, potato, sugarcane, sugar beet,tubers, soybeans or combinations thereof. Sugar-containing plantmaterials include, but are not limited to, molasses, fruit materials,sugar cane, sugar beet or combinations thereof. Cellulose-containingmaterial include, but are not limited to, wood, plant materials orcombinations thereof. In one embodiment, the starch-containing plantmaterial is sugarcane. corn. The plant material may comprise any part ofthe plant, including but not limited to the root, stems, leaves orcombinations thereof.

Conversion of Bio-Glucose to Bio-Ethanol

Both of the Diels-Alder routes to bio-p-xylene described herein rely onthe production of bio-ethanol from bio-glucose:

The process of converting bio-glucose into bio-ethanol involves thetransformation of the sugars of the biomass source material into adistilled pure bio-ethanol product. Various processes and methods forproducing bio-ethanol are well known to those of skill in the art.Bio-ethanol production includes at least the following method steps: (1)milling, (2) liquefaction, (3) saccharification, (4) fermentation and(5) distillation. In some instances, certain steps, such assaccharification and fermentation, can be carried out simultaneously.

Milling can be done either wet or dry. Dry milling is the most commonprocess, and involves grinding whole plant matter into meal andformation of a slurry. Wet milling includes various soaking steps tosoften grains and separate the soluble starches from the germ, fiber andprotein components. Regardless of whether dry or wet milling isperformed, the resultant starch-containing material is mixed with waterand an alpha-amylase and heated to temperatures from about 180° C. toabout 190° C. The slurry then undergoes primary liquefaction in a higherpressure and temperature environment (such as a pressurized jet cookerat 221° F.) before cooling by an atmospheric or vacuum flash condenser.Secondary liquefaction can optionally be performed after primaryliquefaction, and involves maintaining the slurry at a temperature 180°C.-190° C. for an extended period of time (e.g. 1-2 hours) to allow theamylase to break down the starch into short chain dextrins.Saccharification can be performed separately or simultaneously withfermentation. Generally the processes are conducted simultaneously.After liquefaction is complete, the mixture (now referred to as “mash”)is treated with the enzyme glucoamylase to break down dextrins intosimple sugars. An ethanol-producing microorganism is also added to themash to convert the glucose to ethanol and carbon dioxide. Oncesaccarification and fermentation are complete, the mash is distilled toisolate the ethanolic fraction from the mash. The ethanolic fractionoften contains minor quantities of water, which can be removed byrunning the ethanolic fraction through molecular sieves to provide200-proof (anhydrous) ethanol.

The ethanol-producing microorganism can be yeast or bacteria.Ethanol-producing yeast include, but are not limited to, bacteria fromthe genus Saccaromyces. In one embodiment, the ethanol-producing yeastis Saccaromyces cerevisae.

In another embodiment, ethanolic-producing bacteria are from the genusZymomonas, such as, for example Zymomonas mobilis.

Conversion of Bio-Ethanol to Bio-2-Butene

Bio-ethanol can be converted into bio-2-butene by methods known to thoseskilled in the art according to the following scheme:

In one embodiment, bio-ethanol is mixed with diethyl ether and treatedwith an aluminoborate B—Cl catalyst pretreated at 573 K at a temperaturebetween 523 K-573 K (Xu, et al. Journal of the Chemical Society,Chemical Communications, 1992, 17, pages 1228-1229).

In another embodiment, bio-ethanol is converted into bio-2-buteneaccording to the method of Manzer, et al., described in PCT Int. Appl.Publication No. WO 2008/069986. Briefly, vaporous ethanol, eitherdirectly from the distillation process or revaporized, is contacted withat least one basic catalyst at a temperature from about 150° C. to 500°C. and a pressure from about 0.1 MPa to about 20.7 MPa to produce amixture of water and butanols, predominantly 1-butanol.

The basic catalyst can be either a homogeneous or heterogeneouscatalyst. Homogenous catalysts include, but are not limited to, alkalimetal hydroxides. Basic catalysts include, but are not limited to metaloxides, hydroxides, carbonates, silicates, phosphates, aluminates andcombinations thereof. In some embodiments, basic catalysts are metaloxides of one of the following metals: cesium, rubidium, calcium,magnesium, lithium, barium, potassium and lanthanum. In certainembodiments, the basic catalyst can be supported by a catalyst support.Catalyst supports include, but are not limited to, alumina, titania,silica, zirconia, zeolites, carbon, clays, double-layered hydroxides,hydrotacites and combinations thereof.

The base catalyst may further contain a catalyst additive or promoterthan enhances the efficiency of the catalyst. Promoters include, but arenot limited to, Group 8 metals, as well as copper and chromium.

The catalytic conversion of bio-ethanol to water and bio-1-butanol canbe performed in either a batch or continuous mode. Suitable reactorsinclude fixed-bed, adiabatic, fluid-bed, transport bed and moving bed.

In some embodiments, the basic catalyst may become fouled and requireregeneration. The catalyst is regenerated by contacting the catalystwith a gas selected from the group consisting of air, steam, hydrogen,nitrogen or combinations thereof, at an elevated temperature.

The bio-1-butanol and water mixture can be optionally purified to removethe water, thereby producing a partially-purified product consistingprimarily of bio-1-butanol and a small amount of water. In oneembodiment, the bio-1-butanol and water mixture can be purified usingphase separation followed by distillation to provide a solution withgreater than 90% by weight of bio-1-butanol.

The bio-1-butanol and water mixture can then be contacted with at leastone acid catalyst to produce bio-2-butene. The reaction can be conductedin either the liquid or vapor phase. The reaction can be performed at atemperature from about 50° C. to about 450° C. In one embodiment, thereaction is carried out at a temperature from about 100° C. to about250° C.

In one embodiment, the reaction can be carried out at a pressure betweenatmospheric (about 0.1 MPa) to about 20.7 MPa. In another embodiment,the reaction can be carried out at a pressure from about 0.1 MPa toabout 3.45 MPa. The reaction can be performed under inert gaseousconditions, wherein said inert gas is selected from the group consistingof nitrogen, argon and helium.

The acid catalyst can be a homogenous or heterogenous catalyst.Homogenous catalysts include, but are not limited to, inorganic acids,organic sulfonic acids, heteropolyacids, fluoroalkyl sulfonic acids,metal sulfonates, metal trifluoroacetates, compounds thereof andcombinations thereof. Homogeneous catalysts useful for the presentmethods include, but are not limited to, sulfuric acid, fluorosulfonicacid, phosphoric acid, p-toluenesulfonic acid, benzenesulfonic acid,hydrogen fluoride, phosphotungstic acid, phosphomolybdic acid,trifluoromethanesulfonic acid or combinations thereof.

Heterogenous catalysts include, but are not limited to, heterogenousheteropolyacids, natural clay minerals, cation exchange resins, metaloxides, mixed metal oxides, metal salts, zeolites and combinationsthereof. For example, the heterogenous catalyst can be a metal salt,including, but not limited to, metal sulfides, metal sulfates, metalsulfonates, metal nitrates, metal phosphates, metal phosphonates, metalmolybdates, metal tungstates, metal borates or combinations thereof.

The product of the acid catalysis, bio-2-butene, can be purified fromthe reaction mixture by methods known to those of skill in the art,including, but not limited to, decantation, filtration, extraction ormembrane separation.

Conversion of Bio-Ethanol to Bio-1,3-Butadiene

Bio-1,3-butadiene can be prepared from bio-ethanol according to thefollowing scheme:

In one embodiment, bio-ethanol is converted to bio-1,3-butadiene bybeing passed over a metal oxide catalyst at a temperature from about400° C. to about 450° C. The reaction produces bio-1,3-butadiene as wellas water and hydrogen gas.

In another embodiment, bio-ethanol is passed over a magnesiumoxide/silica catalyst in the vapor phase to produce bio-1,3-butadiene.The catalyst can be a mixture of MgO and SiO₂. In another embodiment,the catalyst is a mixture of MgO, SiO₂ and Al₂O₃. The catalysts mayfurther comprise CaHPO₄ or Ca₃(PO₄)₅.

The reaction can be carried out at a temperature from about 350° C. toabout 450° C. or from about 370° C. to about 390° C. Exemplary catalyticconversions of ethanol to 1,3-butadiene are described in Kvisle, et al.,“Transformation of ethanol into 1,3-butadiene over magnesiumoxide/silica catalysts”, Applied Catalysis, 1998, 41(1), pages 117-131and Berak, et al., “Synthesis of butadiene from ethanol II”, PrzemyslChemiczny, 1962, 41(3), pages 130-133.

The bio-1,3-butadiene can be purified from the reaction mixture bymethods known to those of skill in the art, including, but not limitedto, decantation, filtration, extraction or membrane separation.

Dehydration of Bio-Ethanol to Bio-Ethylene

Bio-ethylene serves as the diene in the Diels-Alder cycloaddition withbio-(2E,4E)-hexa-2,4-diene. Bio-ethanol can be dehydrated to formbio-ethylene according to the scheme below:

Methods of preparing ethylene from ethanol are known in the art.Industrial processes for the dehydration of ethanol in a fluidized bedreactor are described in U.S. Pat. No. 4,423,270. The ethanol startingmaterial is obtained from glucose isolated from biomass, as describedabove.

The dehydration of bio-ethanol can be conducted using any knowndehydration catalyst. Dehydration catalysts include, but are not limitedto, alumina, silica-alumina, silicoaluminophosphate (SAPO) molecularsieves (U.S. Pat. Nos. 4,440,871 and 7,199,277), metal-substitutedaluminophosphates (AlPOs; U.S. Patent Publication No. 2010/0249474)activated clays, zeolites, TiO₂/γ-Al₂O₃, Syndol, sulfuric acid,phosphoric acid, substituted phosphoric acids (described in U.S. Pat.No. 4,423,270). Vaporized bio-ethanol can be passed over the dehydrationcatalyst.

The dehydration of bio-ethanol to ethylene may proceed by contactingbio-ethanol with a dehydration catalyst in a fluidized bed reactor at atemperature from about 700° C. to about 1000° C. or from about 750° C.to about 900° C.

Conversion of Bio-Ethanol to Bio-hexa-2,4-diene

Bio-hexa-2,4-diene serves as the dienophile in the Diels-Aldercycloddition with bio-ethylene. Bio-ethanol can be converted tobio-hexa-2,4-diene according to the scheme below:

Methods of preparing hexa-2,4-diene from ethanol are known in the art.The bio-ethanol starting material is obtained from glucose derived fromat least one biomass source, as described above.

In one embodiment, bio-ethanol is combed with methyl ethyl ketone (MEK)and passed over a suitable catalyst, for example silica gel impregnatedwith tantalum oxide (SiO₂—Ta₂O₅), silicamagnesium-tantalum,silica-magnesium-chromium or a Lebedev catalyst.

The reaction can be carried out at a temperature from about 100° C. toabout 500° C. or from about 370° C. to about 450° C.

The bio-hexa-2,4-diene can be obtained from the resultant productaccording to the procedure described in Gorin, et al., Zhurnal ObshcheiKhimii, 1948, 18, pages 1069-1076.

Diels-Alder Cycloaddition of Buta-1,3-diene and 2-butene

Bio-buta-1,3-diene (the diene) and bio-2-butene (the dienophile) arereacted under appropriate Diels-Alder cycloaddition conditions toproduce the [4+2] cycloadduct, bio-4,5-dimethylcyclohex-1-ene, accordingto the following scheme:

Bio-(2E,4E)-hexa-2,4-diene (the diene) and bio-ethylene (the dienophile)are reacted under appropriate Diels-Alder conditions to produce the[4+2] cycloadduct, bio-3,6-dimethylcyclohex-1-ene, according to thefollowing scheme:

The cycloaddition can be carried out in any suitable vessel. In oneembodiment, the cycloaddition is carried out in a tube reactor. Inanother embodiment, the cycloaddition is carried out in a standardpressure vessel.

Efficient reaction times for the methods herein can be accomplished bycontrolling cycloaddition conditions. Cycloaddition conditions caninclude temperature, activity ratio, solvent, pressure and run time. Inone embodiment, efficient reaction times are accomplished by maximizingthe cycloaddition conditions of temperature and activity ratio.

In one embodiment, the cycloaddition is carried out at a temperaturefrom about 100° C. to about 700° C. For example, the cycloaddition canbe carried out at a temperature from about 200° C. to about 700° C.,from about 500° C. to about 700° C., from about 175° C. to about 300° C.or from about 225° C. to about 300° C.

The activity ratio is defined as moles of diene to moles of dienophile.For example, an activity ratio of 1 corresponds to one mole of diene toone mole of dienophile. In another example, an activity ratio of 25corresponds to 25 moles of diene to one mole of dienophile. Generally,higher activity ratios result in faster rates of cycloaddition betweenreactants. Accordingly, the activity ratio of diene to dienophile is atleast 2:1, more preferably at least 5:1, more preferably at least 10:1,more preferably at least 15:1, more preferably at least 20:1, morepreferably at least 25:1, more preferably at least 30:1, more preferablyat least 35:1, more preferably at least 40:1, more preferably at least45:1, more preferably at least 50:1, more preferably at least 55:1, morepreferably at least 60:1; more preferably at least 65:1, more preferablyat least 70:1, more preferably at least 75:1, more preferably at least80:1, more preferably at least 85:1, more preferably at least 90:1, morepreferably at least 95:1, more preferably at least 100:1.

Both the temperature and the activity ratio of the cycloaddition can beoptimized to provide acceptable reaction times. In one embodiment, thetemperature is from about 100° C. to about 700° C. and the activityratio is from about 2:1 to about 100:1. In another embodiment, thetemperature is from about 500° C. to about 700° C. and the activityratio is from about 50:1 to about 100:1.

The cycloaddition can be carried out at atmospheric pressure or underhigher pressures. Generally, higher pressures will accelerate formationof the cycloadduct. The pressure can range from about 100 psi to about10,000 psi, such as from about 200 to about 8,000 psi, from about 400 toabout 6,000 psi or from 600 to 3,000 psi.

The cycloaddition can be carried out in any compatible aqueous ororganic solvent. In one embodiment, a polar organic solvent is used.Suitable organic solvents include, but are not limited to, benzene,toluene, dioxane, xylene, nitrobenzene, acetone, chlorobenzene, ethylether, cyclohexane, hexane, chloroform, dichloromethane,tetrahydrofuran, ethyl acetate, acetone, dimethylformamide,acetonitrile, dimethyl sulfoxide, formic acid, butanol, isopropanol,propanol, ethanol, methanol or combinations thereof.

The course and completion of the cycloaddition can be monitored by anymethod known to those skilled in the art. Suitable methods formonitoring the cycloaddition include thin layer chromatography, gaschromatography, high performance liquid chromatography, massspectroscopy and nuclear magnetic resonance spectroscopy.

One of skill in the art will recognize that the run time for theDiels-Alder cycloaddition described herein will vary based on thereactants, reactant concentration, solvent, temperature and pressure.Accordingly, the run time for the methods described herein can be fromabout 5 minutes to about 24 hours. For example, the run time can be fromabout 30 minutes to about 10 hours or from about 2 hours to about 5hours. The reaction can either be run until all of the reactants havebeen consumed, or can be halted prematurely to allow for isolation ofthe cycloadduct.

In one embodiment, the Diels-Alder cycloaddition for bio-buta-1,3-dieneand bio-2-butene proceeds under the same conditions (e.g. temperature,activity ratio, solvent, pressure, run time) as the Diels-Aldercycloaddition of bio-(2E,4E)-hexa-2,4-diene and bio-ethylene. It isunderstood, however, that in other embodiments the conditions for eachcycloaddition can be different, i.e. run at different temperatures, withdifferent activity ratios, in different solvents, with differentpressures, for different periods of time.

The cycloadducts can be purified by any method known to one of skill inthe art, including, but not limited to, filtration, extraction,chromatography, crystallization or membrane separation.

In some embodiments, the Diels-Alder cycloaddition reaction occurs withgreater than 50% yield. For example, the reaction may proceed in greaterthan 60% yield, greater than 70% yield, greater than 80% yield, greaterthan 90% yield, greater than 95% yield, greater than 97% yield, greaterthan 98% yield or greater than 99% yield.

Dehydrocyclization/Aromatizing of Diels-Alder Cycloadducts

The Diels-Alder cycloadducts (bio-4,5-dimethylcyclohex-1-ene andbio-3,6-dimethylcyclohex-1-ene) can be dehydrocyclized/aromatized toprovide bio-xylenes according to the following scheme:

Aromatization of bio-4,5-diemethylcyclohex-1-ene providesbio-ortho-xylene (bio-o-xylene). Aromatization ofbio-3,6-dimethylcyclohex-1-ene provides bio-para-xylene (bio-p-xylene).

Methods of dehydrocyclizing/aromatizing are known in the art. In oneembodiment, the Diels-Alder cycloadduct is aromatized by contacting thecycloadduct with a dehydrocyclization catalyst in the presence of a H₂Smodifying agent. The H₂S modifying agent can be any compound that willform H₂S under dehydrocyclization conditions. Sulfur-bearing compoundsthat are useful as modifying agents are provided in U.S. Pat. No.3,428,702, and include, but are not limited to, ally sulfide, benzoylsulfide, benzyl disulfide, benzyl sulfide, 2-methyl-1-butanethiol,3-methyl-1-butanethiol, 2-methyl-2-butanethiol, tert-octanethiol, butyldisulfide, butylsulfide, 1,2-ethanedithio, ethanthiol, ethylene sulfide,ethyl disulfide, furfuryl mercaptan, 1-heptanethiol, 1-hexanethiol,isoamyl disulfide, isoamyl sulfide, isobutyl sulfide, methyl disulfide,methyl sulfide, 2-naphthalenethiol, 1-naphthalenethiol, 1-pentanethiol,phenyl disulfide, 1-propanethiol, 2,2′-thiodiethanol,thiophene, acetyldisulfide, benzenesulfonic acid, o-bromo-benzenesulfonic acid,p-bromo-benzenesulfonic acid, o-formyl-benzenesulfonic acid, methylbenzenesulfonic acid, benzyl sulfoxide, butyl sulfoxide,2,2′-dithiophene, butyl sulfate, butyl sulfonate, butyl sulfone, butylsulfoxide, dithiocarbamic acid, thiol-carbamic acid, thiono-carbamicacid, tri-thio-carbonic acid, dithiol-carbonic acid, cetyl sulfate,dodecyl sulfate, 1,2-ethanedisulfonic acid, ethionic anhydride, ethylsulfite, ethyl sulfone, ethyl sulfoxide, ethyl sulfuric acid,methanethiol, methyl sulfoxide, 2-bromothiophene, 2-chlorothiophene,2,5-dimethylthiophene, 2,5-diiodothiophene, 2,3-dimethylthiophene, vinylsulfide, 1-decanol sulfate, methyl sulfate, methyl sulfite,dichlorophenylphosphine sulfide, ethyl methyl sulfide, tetradecylsulfate, thionaphthalene, thioaphthenequinone, 2-methylthiophene,3-methylthiophene, a-toluenethiol, sulfur dissolved in dialkylalkanolamine or combinations thereof.

The dehydrocylization catalyst may be any catalyst known to those ofskill in the art for such purpose. For example, the dehydrocyclizationcatalyst can be an oxide of a Group IV-B, Group V-B or Group VI-Belement. Suitable dehydrocyclization catalysts include, but are notlimited to, oxides of chromium, molybdenum, tungsten, vanadium,titanium, zirconium, thioium, cerium, cesium, antimony, tin, zinc, iron,selenium, copper, platinum, palladium, nickel, cobalt or combinationsthereof.

The reaction can be carried out at a temperature from about 300° C. toabout 650° C., for example from about 450° C. to about 600° C. Thereaction pressure can be from atmospheric to about 50 psi.

In another embodiment, the dehydrocyclization is carried out by passingthe Diels-Alder cycloadduct over a steam-stable Group II metal aluminateimpregnated with a Group VIII metal (U.S. Pat. No. 3,766,291). Forexample, the dehydrocyclization catalyst can be zinc aluminate, tin andplatinum. For example, 0.4-0.6 wt % Pt on zinc aluminate, modified tocontain 1 wt % tin.

In certain embodiments, the Diels-Alder reaction and thedehydrocyclization are carried out in the same reaction vessel. Aftercompletion of the Diels-Alder reaction, the catalyst for thedehydrocyclization can be added.

The reaction can be carried out at a temperature from about 750° F. toabout 1250° F. or from about 900° F. to about 1050° F. The reactionpressures can be from atmospheric to about 500 psi, for example fromabout 50 to about 300 psi.

In yet another embodiment, the dehydrocyclization is carried out bypassing the Diels-Alder cycloadduct over a catalyst consistingessentially of alumina promoted with an alkali metal oxide, and,optionally, chromium oxide (U.S. Pat. No. 4,151,071). In one embodiment,the catalyst consists essentially of alumina promoted with an oxide ofsodium or potassium, rubidium or cesium, and, optionally, chromiumoxide.

The reaction can be carried out at a temperature in the range of about700° F. to about 1100° F., such as from about 800° F. to about 1050° F.The reaction pressures can be from atmospheric to about 300 psi, such asfrom atmospheric to about 50 psi.

The resultant bio-xylene (ortho- or para-isomer) can be purified by anymethod known to one of skill in the art including, but not limited to,filtration, extraction, chromatography, crystallization or membraneseparation.

Isomerization of Bio-o-xylene to Bio-p-xylene

In some embodiments, the bio-p-xylene produced by dehydrocyclization ofbio-3,6-dimethylcyclohex-1-ene is used directly for production ofbio-terephthalic acid (discussed below). The bio-o-xylene produced bydehydrocyclization of bio-4,5-diemethylcyclohex-1-ene, however, shouldbe isomerized to the bio-p-xylene isomer prior to bio-terephthalic acidformation according to the following scheme:

In one embodiment, the bio-o-xylene is passed over an isomerizationcatalyst capable of isomerizing o-xylene to p-xylene, such as a zeolitecatalyst. Zeolite catalysts include, but are not limited to, acidzeolites of the type ZSM-5, ZSM-12, ZSM-35 or ZSM-38 (U.S. Pat. No.3,856,871). In one embodiment, bio-o-xylene is vaporized and passed overa bed containing the isomerization catalyst. In another embodiment, thereaction can be conducted in the liquid phase, with sufficient pressureto retain liquidity of the bio-o-xylene. In another embodiment, thereaction can be conducted in the gaseous phase.

The reaction can be carried out at a temperature from about 300° C. toabout 1000° C., such as from about 500° C. to about 800° C. or about500° C. to about 650° C. The reaction pressure can be from about 150 psito about 700 psi, such as from about 160 psi to about 520 psi.

In another embodiment, the zeolite catalyst also contains a metal havinghydrogenation capability, such as the metals of Group VIII (U.S. Pat.No. RE31,919). In still another embodiment, the zeolite catalyst can beimpregnated with a metal selected from nickel, platinum or a combinationthereof.

The reaction can be carried out at a temperature from about 500° C. toabout 1000° C., such as from about 600° C. to about 800° C. The reactionpressures can be from about 150 psi to about 500 psi, such as from about150 psi to about 300 psi.

The bio-p-xylene can be purified by methods known to those skilled inthe art including, but not limited to, filtration, extraction,chromatography, crystallization or membrane separation.

Oxidation of Bio-p-xylene to Bio-terephthalic Acid

In some embodiments of the present invention, bio-p-xylene can beoxidized to bio-terephthalic acid according to the scheme below:

Methods of oxidizing p-xylene to terephthalic acid are known in the art.In one embodiment, bio-p-xylene can be dissolved in a carboxylicacid-containing solvent and contacted with a catalyst. Suitablecarboxylic acid-containing solvents include, but are not limited to,acetic acid, propionic acid, butyric acid, acetic anhydride orcombinations thereof. In one embodiment, the solvent is acetic acid.

The catalyst can be any cobalt catalyst, as described in U.S. Pat. No.3,334,135, such as the cobalt catalyst is Co(OAc)₂.4H₂O. Manganeseacetate can be used as a co-catalyst. The reaction can be carried out ata temperature from about 30° C. to about 200° C., such as from about120° C. to about 200° C. Oxygen can be passed over the reaction mixtureto effect oxidation.

In another embodiment, bromine-containing compounds can be added to thereaction mixture to accelerate the oxidation (U.S. Pat. No. 3,139,452).In one embodiment, HBr can be used in an amount corresponding to themolar equivalent of the cobalt-containing catalyst.

Bio-terephthalic acid can be esterified by conventional methods toprovide the dimethyl ester, bio-dimethyl terephthalate.

The bio-terephthalic acid or bio-dimethyl terephthalate can be purifiedby methods known to those skilled in the art including, but not limitedto, filtration, extraction, chromatography, crystallization or membraneseparation.

Synthesis of Bio-PET Polymer

The bio-terephthalic acid of the present invention can be used to form abio-PET polymer according to the following scheme:

Methods of forming PET from terephthalic acid and ethylene glycol areknown in the art. Any known conditions can be used for the condensationof bio-terephthalic acid (or bio-dimethyl terephthalate) and ethyleneglycol.

The ethylene glycol can be derived from petrochemical-sources or biomassderived sources. Methods of preparing biomass-derived ethylene glycol(i.e. bio-ethylene glycol) are provided in WO2010/101698. In oneembodiment, bio-terephthalic acid (or bio-dimethyl terephthalate) madeaccording to the methods provided herein is condensed withpetroleum-derived ethylene glycol, resulting in a bio-PET polymer thatis partially derived from biomass starting materials

In another embodiment, bio-terephthalic acid (or bio-dimethylterephthalate) made according to the methods provided herein is reactedwith bio-ethylene glycol, resulting in a bio-PET polymer that is derivedentirely from biological starting materials

The reactants can be subjected to solid state polymerization to form abio-PET resin. For example, the method described in US2005/026728 forpreparing PET can be used to form bio-PET. Briefly, a slurry ofbio-terephthalic acid and bio-ethylene glycol can be prepared.Separately, a titanium complex catalyst is dispersed in a polymermatrix. The matrix is added to the slurry to promote esterification andformation of a polymer melt. The melt is used to form pellets, which aresubsequently solid-state polymerized to obtain bio-PET.

In another embodiment, bio-PET is made by recycling scrap PET polymerthrough a degradative transesterification or hydrolysis process.

The reactants can by polymerized in a catalyst solution at atmosphericpressure to form a bio-PET polymer. Acidic or basic catalyst can beused. Suitable catalysts include, but are not limited to,antimony-containing catalysts, germanium-containing catalysts,titanium-containing catalyst and cobalt-containing catalysts. Exemplaryantimony-containing catalysts include, but are not limited to, antimonytrioxide, antimony triacetate or combinations thereof. Exemplarygermanium-containing catalysts include, but are not limited to,germanium dioxide. Exemplary titanium-containing catalysts include, butare not limited to, tetra-n-propyltitanate, tetra-isopropyl titanate,tetra-n-butyl titanate, tetraphenyl titanate, tetracyclohexyl titanate,tetrabenzyl titanate, tetra-n-butyl titanate tetramer, titanium acetate,titanium oxalates, sodium or potassium titanates, titanium halides,titanate hexafluorides of potassium, manganese and ammonium, titaniumacetylacetate, titanium alkoxides, titanate phosphites, or combinationsthereof. Mixtures of various metal-containing catalysts can also beutilized.

The condensation reaction can also be induced using a coupling agent.Suitable coupling agents include, but are not limited to, carbodiimidecoupling agents, for example N,N′-dicyclohexylcarbodiimide (DCC),N,N′-diisopropylcarbodiimide (DIC) or1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDCI).Additives to promote efficient coupling can also be included, such as1-hydroxy-1,2,3-benzotriazole (HOBt), HOBt/CuCl₂,7-aza-1-hydroxy-1,2,3-benzotriazole (HOAt),3,4-dihydro-3-hydroxy-4-oxo-1,2,3-benzotriazole (HOOBt),N-hydroxysuccinimide (NHS) or 3-sulfo-1-hydroxysuccinimide (S—NHS).

The reaction can be carried out a temperature from about 100° C. toabout 500° C. For example, the reaction of bio-terephthalic acid andethylene glycol can be carried out at a temperature from about 220° C.to about 260° C. In another example, the reaction of bio-dimethylterephthalate and ethylene glycol can be carried out at a temperaturefrom about 150° C. to about 280° C.

Packaging

The bio-PET polymer formed according to the method of the presentinvention can be used to form a bio-PET resin, which can then be formedinto bio-PET performs or bio-PET packaging. The term packaging, as usedherein, refers to any component of an article of packaging, includingclosures, labels and secondary packaging. In one embodiment, the bio-PETpackaging is a food or beverage container or product, or any closure(e.g., cap), label or secondary packaging associated with the same. Foodcontainers include, but are not limited to, disposable Tupperware,reusable Tupperware, and containers for commercial food products.Beverage containers include, but are not limited to, bottles and cups.Food products include, but are not limited to, straws, toothpicks,disposable plates and disposable cutlery.

EXAMPLES Example 1 Diels-Alder Cycloaddition of Hexa-2,4-diene andEthylene

The reaction coordinate of the Diels-Alder cycloaddition ofhexa-2,4-diene and ethylene to give 3,6-dimethylcyclohex-1-ene is shownin FIG. 1. Computationally calculated temperature, activity ratios andreaction rates of the Diels-Alder cycloaddition are shown in Table 1,and are based on the Eyering equation:k=(k _(B) t/h)^((−Ea/RT))

-   where k=rate constant;-   K_(B)=Boltzmann constant;-   T=temperature;-   h=Plank's constant; and-   Ea=Activation energy (143.1 kJ/mol)

The “Ratio” is defined as the moles of ethylene to moles ofhexa-2,4-diene.

TABLE 1 Temperature Ratio K ° C. k (1/s) 1 2 5 10 25 50 100 298.15 255.27E−16 5.27E−16 1.05E−15 2.64E−15 5.27E−15 1.32E−14 2.64E−14 5.27E−14303.15 30 1.39E−15 1.39E−15 2.78E−15 6.94E−15 1.39E−14 3.47E−14 6.94E−141.39E−13 308.15 35 3.55E−15 3.55E−15 7.09E−15 1.77E−14 3.55E−14 8.87E−141.77E−13 3.55E−13 313.15 40 8.79E−15 8.79E−15 1.76E−14 4.40E−14 8.79E−142.20E−13 4.40E−13 8.79E−13 318.15 45 2.12E−14 2.12E−14 4.24E−14 1.06E−132.12E−13 5.30E−13 1.06E−12 2.12E−12 323.15 50 4.97E−14 4.97E−14 9.94E−142.49E−13 4.97E−13 1.24E−12 2.49E−12 4.97E−12 328.15 55 1.14E−13 1.14E−132.27E−13 5.68E−13 1.14E−12 2.84E−12 5.68E−12 1.14E−11 333.15 60 2.53E−132.53E−13 5.07E−13 1.27E−12 2.53E−12 6.34E−12 1.27E−11 2.53E−11 338.15 655.52E−13 5.52E−13 1.10E−12 2.76E−12 5.52E−12 1.38E−11 2.76E−11 5.52E−11343.15 70 1.18E−12 1.18E−12 2.35E−12 5.88E−12 1.18E−11 2.94E−11 5.88E−111.18E−10 348.15 75 2.45E−12 2.45E−12 4.91E−12 1.23E−11 2.45E−11 6.13E−111.23E−10 2.45E−10 353.15 80 5.01E−12 5.01E−12 1.00E−11 2.51E−11 5.01E−111.25E−10 2.51E−10 5.01E−10 358.15 85 1.00E−11 1.00E−11 2.01E−11 5.02E−111.00E−10 2.51E−10 5.02E−10 1.00E−09 363.15 90 1.97E−11 1.97E−11 3.94E−119.86E−11 1.97E−10 4.93E−10 9.86E−10 1.97E−09 368.15 95 3.81E−11 3.81E−117.61E−11 1.90E−10 3.81E−10 9.52E−10 1.90E−09 3.81E−09 373.15 1007.22E−11 7.22E−11 1.44E−10 3.61E−10 7.22E−10 1.80E−09 3.61E−09 7.22E−09378.15 105 1.35E−10 1.35E−10 2.69E−10 6.73E−10 1.35E−09 3.37E−096.73E−09 1.35E−08 383.15 110 2.47E−10 2.47E−10 4.94E−10 1.24E−092.47E−09 6.18E−09 1.24E−08 2.47E−08 388.15 115 4.46E−10 4.46E−108.93E−10 2.23E−09 4.46E−09 1.12E−08 2.23E−08 4.46E−08 393.15 1207.95E−10 7.95E−10 1.59E−09 3.97E−09 7.95E−09 1.99E−08 3.97E−08 7.95E−08398.15 125 1.39E−09 1.39E−09 2.79E−09 6.97E−09 1.39E−08 3.49E−086.97E−08 1.39E−07 403.15 130 2.41E−09 2.41E−09 4.83E−09 1.21E−082.41E−08 6.03E−08 1.21E−07 2.41E−07 408.15 135 4.12E−09 4.12E−098.25E−09 2.06E−08 4.12E−08 1.03E−07 2.06E−07 4.12E−07 413.15 1406.95E−09 6.95E−09 1.39E−08 3.48E−08 6.95E−08 1.74E−07 3.48E−07 6.95E−07418.15 145 1.16E−08 1.16E−08 2.32E−08 5.79E−08 1.16E−07 2.89E−075.79E−07 1.16E−06 423.15 150 1.91E−08 1.91E−08 3.81E−08 9.53E−081.91E−07 4.76E−07 9.53E−07 1.91E−06 428.15 155 3.10E−08 3.10E−086.20E−08 1.55E−07 3.10E−07 7.75E−07 1.55E−06 3.10E−06 433.15 1604.99E−08 4.99E−08 9.98E−08 2.49E−07 4.99E−07 1.25E−06 2.49E−06 4.99E−06438.15 165 7.94E−08 7.94E−08 1.59E−07 3.97E−07 7.94E−07 1.99E−063.97E−06 7.94E−06 443.15 170 1.25E−07 1.25E−07 2.50E−07 6.26E−071.25E−06 3.13E−06 6.26E−06 1.25E−05 448.15 175 1.95E−07 1.95E−073.90E−07 9.76E−07 1.95E−06 4.88E−06 9.76E−06 1.95E−05 453.15 1803.02E−07 3.02E−07 6.03E−07 1.51E−06 3.02E−06 7.54E−06 1.51E−05 3.02E−05458.15 185 4.61E−07 4.61E−07 9.23E−07 2.31E−06 4.61E−06 1.15E−052.31E−05 4.61E−05 463.15 190 7.00E−07 7.00E−07 1.40E−06 3.50E−067.00E−06 1.75E−05 3.50E−05 7.00E−05 468.15 195 1.05E−06 1.05E−062.10E−06 5.26E−06 1.05E−05 2.63E−05 5.26E−05 1.05E−04 473.15 2001.57E−06 1.57E−06 3.14E−06 7.84E−06 1.57E−05 3.92E−05 7.84E−05 1.57E−04478.15 205 2.32E−06 2.32E−06 4.64E−06 1.16E−05 2.32E−05 5.79E−051.16E−04 2.32E−04 483.15 210 3.40E−06 3.40E−06 6.80E−06 1.70E−053.40E−05 8.50E−05 1.70E−04 3.40E−04 488.15 215 4.95E−06 4.95E−069.89E−06 2.47E−05 4.95E−05 1.24E−04 2.47E−04 4.95E−04 493.15 2207.15E−06 7.15E−06 1.43E−05 3.57E−05 7.15E−05 1.79E−04 3.57E−04 7.15E−04498.15 225 1.02E−05 1.02E−05 2.05E−05 5.12E−05 1.02E−04 2.56E−045.12E−04 1.02E−03 503.15 230 1.46E−05 1.46E−05 2.92E−05 7.29E−051.46E−04 3.65E−04 7.29E−04 1.46E−03 508.15 235 2.06E−05 2.06E−054.13E−05 1.03E−04 2.06E−04 5.16E−04 1.03E−03 2.06E−03 513.15 2402.90E−05 2.90E−05 5.80E−05 1.45E−04 2.90E−04 7.24E−04 1.45E−03 2.90E−03518.15 245 4.04E−05 4.04E−05 8.09E−05 2.02E−04 4.04E−04 1.01E−032.02E−03 4.04E−03 523.15 250 5.61E−05 5.61E−05 1.12E−04 2.80E−045.61E−04 1.40E−03 2.80E−03 5.61E−03 528.15 255 7.73E−05 7.73E−051.55E−04 3.87E−04 7.73E−04 1.93E−03 3.87E−03 7.73E−03 533.15 2601.06E−04 1.06E−04 2.12E−04 5.30E−04 1.06E−03 2.65E−03 5.30E−03 1.06E−02538.15 265 1.44E−04 1.44E−04 2.89E−04 7.22E−04 1.44E−03 3.61E−037.22E−03 1.44E−02 543.15 270 1.96E−04 1.96E−04 3.91E−04 9.78E−041.96E−03 4.89E−03 9.78E−03 1.96E−02 548.15 275 2.64E−04 2.64E−045.27E−04 1.32E−03 2.64E−03 6.59E−03 1.32E−02 2.64E−02 553.15 2803.53E−04 3.53E−04 7.06E−04 1.77E−03 3.53E−03 8.83E−03 1.77E−02 3.53E−02558.15 285 4.71E−04 4.71E−04 9.42E−04 2.35E−03 4.71E−03 1.18E−022.35E−02 4.71E−02 563.15 290 6.25E−04 6.25E−04 1.25E−03 3.12E−036.25E−03 1.56E−02 3.12E−02 6.25E−02 568.15 295 8.25E−04 8.25E−041.65E−03 4.12E−03 8.25E−03 2.06E−02 4.12E−02 8.25E−02 573.15 3001.08E−03 1.08E−03 2.17E−03 5.42E−03 1.08E−02 2.71E−02 5.42E−02 1.08E−01578.15 305 1.42E−03 1.42E−03 2.84E−03 7.09E−03 1.42E−02 3.54E−027.09E−02 1.42E−01 583.15 310 1.85E−03 1.85E−03 3.69E−03 9.23E−031.85E−02 4.61E−02 9.23E−02 1.85E−01 588.15 315 2.39E−03 2.39E−034.79E−03 1.20E−02 2.39E−02 5.98E−02 1.20E−01 2.39E−01 593.15 3203.09E−03 3.09E−03 6.18E−03 1.54E−02 3.09E−02 7.72E−02 1.54E−01 3.09E−01598.15 325 3.97E−03 3.97E−03 7.94E−03 1.98E−02 3.97E−02 9.92E−021.98E−01 3.97E−01 603.15 330 5.08E−03 5.08E−03 1.02E−02 2.54E−025.08E−02 1.27E−01 2.54E−01 5.08E−01 608.15 335 6.48E−03 6.48E−031.30E−02 3.24E−02 6.48E−02 1.62E−01 3.24E−01 6.48E−01 613.15 3408.23E−03 8.23E−03 1.65E−02 4.11E−02 8.23E−02 2.06E−01 4.11E−01 8.23E−01618.15 345 1.04E−02 1.04E−02 2.08E−02 5.20E−02 1.04E−01 2.60E−015.20E−01 1.04E+00 623.15 350 1.31E−02 1.31E−02 2.62E−02 6.56E−021.31E−01 3.28E−01 6.56E−01 1.31E+00 628.15 355 1.65E−02 1.65E−023.29E−02 8.24E−02 1.65E−01 4.12E−01 8.24E−01 1.65E+00 633.15 3602.06E−02 2.06E−02 4.12E−02 1.03E−01 2.06E−01 5.15E−01 1.03E+00 2.06E+00638.15 365 2.57E−02 2.57E−02 5.14E−02 1.29E−01 2.57E−01 6.43E−011.29E+00 2.57E+00 643.15 370 3.20E−02 3.20E−02 6.39E−02 1.60E−013.20E−01 7.99E−01 1.60E+00 3.20E+00 648.15 375 3.96E−02 3.96E−027.92E−02 1.98E−01 3.96E−01 9.90E−01 1.98E+00 3.96E+00 653.15 3804.89E−02 4.89E−02 9.78E−02 2.44E−01 4.89E−01 1.22E+00 2.44E+00 4.89E+00658.15 385 6.02E−02 6.02E−02 1.20E−01 3.01E−01 6.02E−01 1.50E+003.01E+00 6.02E+00 663.15 390 7.39E−02 7.39E−02 1.48E−01 3.69E−017.39E−01 1.85E+00 3.69E+00 7.39E+00 668.15 395 9.04E−02 9.04E−021.81E−01 4.52E−01 9.04E−01 2.26E+00 4.52E+00 9.04E+00 673.15 4001.10E−01 1.10E−01 2.20E−01 5.51E−01 1.10E+00 2.76E+00 5.51E+00 1.10E+01678.15 405 1.34E−01 1.34E−01 2.68E−01 6.71E−01 1.34E+00 3.35E+006.71E+00 1.34E+01 683.15 410 1.63E−01 1.63E−01 3.25E−01 8.13E−011.63E+00 4.07E+00 8.13E+00 1.63E+01 688.15 415 1.97E−01 1.97E−013.94E−01 9.84E−01 1.97E+00 4.92E+00 9.84E+00 1.97E+01 693.15 4202.37E−01 2.37E−01 4.75E−01 1.19E+00 2.37E+00 5.93E+00 1.19E+01 2.37E+01698.15 425 2.86E−01 2.86E−01 5.71E−01 1.43E+00 2.86E+00 7.14E+001.43E+01 2.86E+01

Example 2 Diels-Alder Cycloaddition of Hexa-2,4-diene and Ethylene

The reaction coordinate of the Diels-Alder cycloaddition ofbuta-1,3-diene and 2-butene to produce the [4+2] cycloadduct,4,5-dimethylcyclohex-1-ene is shown in FIG. 2. Computationallycalculated temperature, activity ratios and reaction rates of theDiels-Alder cycloaddition are shown in Table 2, and are based on theEyering equation:k=(k _(B) t/h)^((−Ea/RT))

-   where k=rate constant;-   K_(B)=Boltzmann constant;-   h=Plank's constant;-   T=temperature; and-   Ea=Activation energy (131.05 kJ/mol)

The “Ratio” is defined as the molar concentration of 2-butene to themolar concentration of buta-1,3-diene.

TABLE 2 Temperature Ratio K ° C. k (1/s) 1 2 5 10 25 50 100 298.15 256.81E−14 6.81E−14 1.36E−13 3.40E−13 6.81E−13 1.70E−12 3.40E−12 6.81E−12303.15 30 1.66E−13 1.66E−13 3.31E−13 8.28E−13 1.66E−12 4.14E−12 8.28E−121.66E−11 308.15 35 3.91E−13 3.91E−13 7.82E−13 1.96E−12 3.91E−12 9.78E−121.96E−11 3.91E−11 313.15 40 9.00E−13 9.00E−13 1.80E−12 4.50E−12 9.00E−122.25E−11 4.50E−11 9.00E−11 318.15 45 2.02E−12 2.02E−12 4.03E−12 1.01E−112.02E−11 5.04E−11 1.01E−10 2.02E−10 323.15 50 4.41E−12 4.41E−12 8.82E−122.20E−11 4.41E−11 1.10E−10 2.20E−10 4.41E−10 328.15 55 9.41E−12 9.41E−121.88E−11 4.71E−11 9.41E−11 2.35E−10 4.71E−10 9.41E−10 333.15 60 1.96E−111.96E−11 3.93E−11 9.82E−11 1.96E−10 4.91E−10 9.82E−10 1.96E−09 338.15 654.01E−11 4.01E−11 8.03E−11 2.01E−10 4.01E−10 1.00E−09 2.01E−09 4.01E−09343.15 70 8.04E−11 8.04E−11 1.61E−10 4.02E−10 8.04E−10 2.01E−09 4.02E−098.04E−09 348.15 75 1.58E−10 1.58E−10 3.15E−10 7.88E−10 1.58E−09 3.94E−097.88E−09 1.58E−08 353.15 80 3.04E−10 3.04E−10 6.07E−10 1.52E−09 3.04E−097.59E−09 1.52E−08 3.04E−08 358.15 85 5.74E−10 5.74E−10 1.15E−09 2.87E−095.74E−09 1.44E−08 2.87E−08 5.74E−08 363.15 90 1.07E−09 1.07E−09 2.13E−095.34E−09 1.07E−08 2.67E−08 5.34E−08 1.07E−07 368.15 95 1.95E−09 1.95E−093.90E−09 9.75E−09 1.95E−08 4.88E−08 9.75E−08 1.95E−07 373.15 1003.51E−09 3.51E−09 7.02E−09 1.75E−08 3.51E−08 8.77E−08 1.75E−07 3.51E−07378.15 105 6.22E−09 6.22E−09 1.24E−08 3.11E−08 6.22E−08 1.55E−073.11E−07 6.22E−07 383.15 110 1.09E−08 1.09E−08 2.17E−08 5.43E−081.09E−07 2.71E−07 5.43E−07 1.09E−06 388.15 115 1.87E−08 1.87E−083.74E−08 9.34E−08 1.87E−07 4.67E−07 9.34E−07 1.87E−06 393.15 1203.17E−08 3.17E−08 6.34E−08 1.59E−07 3.17E−07 7.93E−07 1.59E−06 3.17E−06398.15 125 5.31E−08 5.31E−08 1.06E−07 2.66E−07 5.31E−07 1.33E−062.66E−06 5.31E−06 403.15 130 8.79E−08 8.79E−08 1.76E−07 4.40E−078.79E−07 2.20E−06 4.40E−06 8.79E−06 408.15 135 1.44E−07 1.44E−072.87E−07 7.18E−07 1.44E−06 3.59E−06 7.18E−06 1.44E−05 413.15 1402.32E−07 2.32E−07 4.64E−07 1.16E−06 2.32E−06 5.80E−06 1.16E−05 2.32E−05418.15 145 3.71E−07 3.71E−07 7.41E−07 1.85E−06 3.71E−06 9.27E−061.85E−05 3.71E−05 423.15 150 5.86E−07 5.86E−07 1.17E−06 2.93E−065.86E−06 1.46E−05 2.93E−05 5.86E−05 428.15 155 9.15E−07 9.15E−071.83E−06 4.58E−06 9.15E−06 2.29E−05 4.58E−05 9.15E−05 433.15 1601.42E−06 1.42E−06 2.83E−06 7.08E−06 1.42E−05 3.54E−05 7.08E−05 1.42E−04438.15 165 2.17E−06 2.17E−06 4.34E−06 1.09E−05 2.17E−05 5.43E−051.09E−04 2.17E−04 443.15 170 3.29E−06 3.29E−06 6.59E−06 1.65E−053.29E−05 8.24E−05 1.65E−04 3.29E−04 448.15 175 4.95E−06 4.95E−069.91E−06 2.48E−05 4.95E−05 1.24E−04 2.48E−04 4.95E−04 453.15 1807.39E−06 7.39E−06 1.48E−05 3.69E−05 7.39E−05 1.85E−04 3.69E−04 7.39E−04458.15 185 1.09E−05 1.09E−05 2.18E−05 5.46E−05 1.09E−04 2.73E−045.46E−04 1.09E−03 463.15 190 1.60E−05 1.60E−05 3.20E−05 8.00E−051.60E−04 4.00E−04 8.00E−04 1.60E−03 468.15 195 2.33E−05 2.33E−054.65E−05 1.16E−04 2.33E−04 5.81E−04 1.16E−03 2.33E−03 473.15 2003.35E−05 3.35E−05 6.71E−05 1.68E−04 3.35E−04 8.39E−04 1.68E−03 3.35E−03478.15 205 4.80E−05 4.80E−05 9.61E−05 2.40E−04 4.80E−04 1.20E−032.40E−03 4.80E−03 483.15 210 6.83E−05 6.83E−05 1.37E−04 3.41E−046.83E−04 1.71E−03 3.41E−03 6.83E−03 488.15 215 9.63E−05 9.63E−051.93E−04 4.82E−04 9.63E−04 2.41E−03 4.82E−03 9.63E−03 493.15 2201.35E−04 1.35E−04 2.70E−04 6.75E−04 1.35E−03 3.38E−03 6.75E−03 1.35E−02498.15 225 1.88E−04 1.88E−04 3.76E−04 9.40E−04 1.88E−03 4.70E−039.40E−03 1.88E−02 503.15 230 2.60E−04 2.60E−04 5.20E−04 1.30E−032.60E−03 6.50E−03 1.30E−02 2.60E−02 508.15 235 3.57E−04 3.57E−047.15E−04 1.79E−03 3.57E−03 8.94E−03 1.79E−02 3.57E−02 513.15 2404.88E−04 4.88E−04 9.77E−04 2.44E−03 4.88E−03 1.22E−02 2.44E−02 4.88E−02518.15 245 6.63E−04 6.63E−04 1.33E−03 3.32E−03 6.63E−03 1.66E−023.32E−02 6.63E−02 523.15 250 8.96E−04 8.96E−04 1.79E−03 4.48E−038.96E−03 2.24E−02 4.48E−02 8.96E−02 528.15 255 1.20E−03 1.20E−032.41E−03 6.01E−03 1.20E−02 3.01E−02 6.01E−02 1.20E−01 533.15 2601.61E−03 1.61E−03 3.21E−03 8.03E−03 1.61E−02 4.02E−02 8.03E−02 1.61E−01538.15 265 2.13E−03 2.13E−03 4.27E−03 1.07E−02 2.13E−02 5.33E−021.07E−01 2.13E−01 543.15 270 2.82E−03 2.82E−03 5.64E−03 1.41E−022.82E−02 7.05E−02 1.41E−01 2.82E−01 548.15 275 3.71E−03 3.71E−037.42E−03 1.85E−02 3.71E−02 9.27E−02 1.85E−01 3.71E−01 553.15 2804.85E−03 4.85E−03 9.71E−03 2.43E−02 4.85E−02 1.21E−01 2.43E−01 4.85E−01558.15 285 6.32E−03 6.32E−03 1.26E−02 3.16E−02 6.32E−02 1.58E−013.16E−01 6.32E−01 563.15 290 8.19E−03 8.19E−03 1.64E−02 4.10E−028.19E−02 2.05E−01 4.10E−01 8.19E−01 568.15 295 1.06E−02 1.06E−022.12E−02 5.29E−02 1.06E−01 2.64E−01 5.29E−01 1.06E+00 573.15 3001.36E−02 1.36E−02 2.72E−02 6.80E−02 1.36E−01 3.40E−01 6.80E−01 1.36E+00578.15 305 1.74E−02 1.74E−02 3.48E−02 8.70E−02 1.74E−01 4.35E−018.70E−01 1.74E+00 583.15 310 2.22E−02 2.22E−02 4.43E−02 1.11E−012.22E−01 5.54E−01 1.11E+00 2.22E+00 588.15 315 2.81E−02 2.81E−025.63E−02 1.41E−01 2.81E−01 7.03E−01 1.41E+00 2.81E+00 593.15 3203.56E−02 3.56E−02 7.11E−02 1.78E−01 3.56E−01 8.89E−01 1.78E+00 3.56E+00598.15 325 4.48E−02 4.48E−02 8.95E−02 2.24E−01 4.48E−01 1.12E+002.24E+00 4.48E+00 603.15 330 5.62E−02 5.62E−02 1.12E−01 2.81E−015.62E−01 1.40E+00 2.81E+00 5.62E+00 608.15 335 7.02E−02 7.02E−021.40E−01 3.51E−01 7.02E−01 1.76E+00 3.51E+00 7.02E+00 613.15 3408.74E−02 8.74E−02 1.75E−01 4.37E−01 8.74E−01 2.19E+00 4.37E+00 8.74E+00618.15 345 1.09E−01 1.09E−01 2.17E−01 5.43E−01 1.09E+00 2.71E+005.43E+00 1.09E+01 623.15 350 1.34E−01 1.34E−01 2.69E−01 6.71E−011.34E+00 3.36E+00 6.71E+00 1.34E+01 628.15 355 1.66E−01 1.66E−013.31E−01 8.28E−01 1.66E+00 4.14E+00 8.28E+00 1.66E+01 633.15 3602.03E−01 2.03E−01 4.07E−01 1.02E+00 2.03E+00 5.08E+00 1.02E+01 2.03E+01638.15 365 2.49E−01 2.49E−01 4.98E−01 1.25E+00 2.49E+00 6.23E+001.25E+01 2.49E+01 643.15 370 3.04E−01 3.04E−01 6.09E−01 1.52E+003.04E+00 7.61E+00 1.52E+01 3.04E+01 648.15 375 3.70E−01 3.70E−017.41E−01 1.85E+00 3.70E+00 9.26E+00 1.85E+01 3.70E+01 653.15 3804.50E−01 4.50E−01 8.99E−01 2.25E+00 4.50E+00 1.12E+01 2.25E+01 4.50E+01658.15 385 5.44E−01 5.44E−01 1.09E+00 2.72E+00 5.44E+00 1.36E+012.72E+01 5.44E+01 663.15 390 6.57E−01 6.57E−01 1.31E+00 3.29E+006.57E+00 1.64E+01 3.29E+01 6.57E+01 668.15 395 7.91E−01 7.91E−011.58E+00 3.95E+00 7.91E+00 1.98E+01 3.95E+01 7.91E+01 673.15 4009.49E−01 9.49E−01 1.90E+00 4.75E+00 9.49E+00 2.37E+01 4.75E+01 9.49E+01678.15 405 1.14E+00 1.14E+00 2.27E+00 5.68E+00 1.14E+01 2.84E+015.68E+01 1.14E+02 683.15 410 1.36E+00 1.36E+00 2.71E+00 6.79E+001.36E+01 3.39E+01 6.79E+01 1.36E+02 688.15 415 1.62E+00 1.62E+003.23E+00 8.08E+00 1.62E+01 4.04E+01 8.08E+01 1.62E+02 693.15 4201.92E+00 1.92E+00 3.84E+00 9.61E+00 1.92E+01 4.80E+01 9.61E+01 1.92E+02698.15 425 2.28E+00 2.28E+00 4.55E+00 1.14E+01 2.28E+01 5.69E+011.14E+02 2.28E+02Discussion

Tables 1 and 2 illustrate that increasing the activity ratio of diene todienophile, regardless of temperature, increases the rate of thecycloaddition reaction. Similarly, increasing the temperature of thereaction, regardless of the activity ratio, increases the rate of thecycloaddition reaction. The fastest reaction rates occur at maximumactivity ratio and maximum temperature.

What is claimed is:
 1. A method of preparing bio-p-xylene comprising:deriving bio-glucose from at least one biomass source; convertingbio-glucose to bio-ethanol; converting a first portion of bio-ethanol tobio-2-butene; converting a second portion of bio-ethanol tobio-1,3-butadiene; reacting bio-2-butene and bio-1,3-butadiene underDiels-Alder cycloaddition conditions to formbio-4,5-dimethylcyclohex-1-ene; dehydrocyclizingbio-4,5-dimethylcyclohex-1-ene to bio-o-xylene; and isomerizingbio-o-xylene to bio-p-xylene.
 2. The method of claim 1, furthercomprising oxidation of bio-p-xylene to provide bio-terephthalic acid.3. The method of claim 1, wherein the activity ratio of the Diels-Aldercycloaddition is at least about 2:1.
 4. The method of claim 1, whereinthe activity ratio of the Diels-Alder cycloaddition is at least about100:1.
 5. The method of claim 1, wherein the temperature of theDiels-Alder cycloaddition is from about 500° C. to about 700° C.
 6. Themethod of claim 1, wherein the temperature of the Diels-Aldercycloaddition is from about 500° C. to about 700° C. and the activityratio is from about 50:1 to about 100:1.
 7. The methods of claim 1,wherein the at least one biomass source is selected from the groupconsisting of corn, maize, sorghum, barley, wheat, rye, rice, millet,barley, potato, sugarcane, sugar beet, tubers, soybeans, molasses, fruitmaterials, sugar cane, sugar beet, wood, plant materials or combinationsthereof.